Yoshio Ice goes with transcritical CO₂ in warm climate

Continuing the growth of CO₂ transcritical systems in Japan’s cold storage industry, Fukuoka-based Yoshio Ice Manufacturing & Refrigeration (Yoshio Ice) installed three Japanese-manufactured CO₂ transcritical systems at one of its cold storage facilities in April 2018.

The plant’s location: Fukuoka, Japan, on Kyushu island, which is the southernmost of Japan’s main islands. The region experiences some of Japan’s hottest and most humid climates with temperatures sometimes reaching 35°C (95°F) during the summer months.

But energy performance and reliability of transcritical CO₂ systems in hot climates have been less and less of a concern with end users around the world as CO₂ technology like ejectors, parallel compressors and adiabatic condensers has rapidly advanced in recent years.

Energy performance data at the Yoshio Ice facility has helped bolster this confidence – a point made at the ATMOsphere Japan 2019 conference held in Tokyo in February.

The three CO₂ Booster Super Green systems installed at the Fukuoka cold storage facility were provided by Tokyo-based manufacturer Nihon Netsugen Systems (NNS), which unveiled the system last year at the FOOMA Japan exhibition. The systems use a water-spraying system with the gas cooler to maintain efficiency in high ambient temperatures.

During the ATMOsphere Japan 2019 conference, Nihon Netsugen Systems’ president, Katsuhiko Harada, presented energy performance metrics for the facility from April through December 2018. The power consumption for the period was 27 kWh/m³ – less than what was predicted (around 35 kWh/m³), and far less than Japan’s industry annual average of around 61 kWh/m³.

Inside Yoshio Ice's Fukuoka cold storage facility where the CO₂ transcritical systems were installed.

Choosing CO₂ for Safety

Touring the facility in June of 2018, Accelerate Japan (a Japanese-language sister publication to Accelerate Magazine) learned more about how the project originated.

The three CO₂ transcritical systems service one 4,700-m³ frozen storage room (at -25°C/-13°F), as well as a 3,700-m3 cold room (at 5°C/41°F) and a 4,700-m³ loading area (at 5°C). Shigekatsu Koganemaru, Yoshio Ice’s president, first heard about NNS’s CO₂ transcritical system at a general meeting of the Japan Association of Refrigerated Warehouses (JARW) in 2016.

“After speaking with NNS and learning about the system’s technical specifications in detail, I determined that the system had reached a sufficiently usable level,” said Koganemaru. “We then decided to install it at our new warehouse which was being planned at the time.”

Tour attendees inspect the CO₂ Booster Super Green system provided by Japanese OEM Nihon Netsugen Systems.

Koganemaru, who also spoke at the ATMOsphere Japan 2018 event, explained that as a board member of JARW and vice-chairman of the association’s Environment and Safety Committee, he understands the important role to be played by natural refrigerants in this sector, both now and in the future.

According to 2016 JARW data, 14% of Japan’s cold storage facilities use NH₃/CO₂ cascade systems and 11.3% employ NH₃ systems, while 68% still utilize R22. But Koganemaru preferred to use a CO₂ transcritical system over an NH3/CO₂ cascade or traditional NH₃ system out of concern for his employees’ safety.

Koganemaru, who has previously worked in factories where ammonia was considered dangerous to handle, acknowledged that safety standards used to be more ambiguous than they are now. He said it was once normal to be exposed to intense odors when liquid ammonia leaked from valves, sometimes leading to burns or other minor injuries.

Helped by Subsidies

The installation of the CO₂ transcritical systems at Yoshio Ice were supported by subsidies provided by the Japanese government in fiscal year 2017 (which ends March 31, 2018).

The majority of the refrigerated warehouse industry consists of small companies that benefit from subsidies, said Koganemaru. “For these companies, the replacement of factory equipment and machinery is a very big investment. That is why subsidies that bear the burden of half of the installation costs are very much appreciated.”

These subsidies are expected to continue into this year with the Japanese Ministry of the Environment already having confirmed that it has set the budget for fiscal year 2019 at ¥7.4 billion ($65 million).

Story originally published in the June 2019 edition of Accelerate Magazine.